noun
Uncommon
phi
feye
Phi (noun) means the 21st letter of the Greek alphabet (Φ, φ), often used as a symbol in science and mathematics. Example: “In the equation, phi represents the phase angle.”
noun
1
The 21st letter of the Greek alphabet (Φ, φ), often used as a symbol in science and mathematics.
"In the equation, phi represents the phase angle."
2
The golden ratio, approximately 1.618, often represented by this letter.
"The proportions of the building were designed around phi."
How to use phi
Learner’s notesIn plain EnglishA Greek letter, commonly used as shorthand for the golden ratio in math and design.
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Word forms
- Plural
- phis
Fill the gap
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In the equation, _____ represents the phase angle.
Etymology
From the Greek letter phei, borrowed into Latin and then English as "phi."
Frequently asked questions
What does “phi” mean?
The word “phi” means the 21st letter of the Greek alphabet (Φ, φ), often used as a symbol in science and mathematics. In plain terms, a Greek letter, commonly used as shorthand for the golden ratio in math and design.
How do you pronounce “phi”?
“Phi” is pronounced feye (/faɪ/ in IPA).
How do you use “phi” in a sentence?
Here is “phi” used in a sentence: “In the equation, phi represents the phase angle.”
What part of speech is “phi”?
“Phi” is a noun.
Where does the word “phi” come from?
The word “phi” comes from Latin. From the Greek letter phei, borrowed into Latin and then English as "phi.".
Is “phi” a common word?
“Phi” is an uncommon word in modern English.
How many meanings does “phi” have?
“Phi” has 2 distinct senses listed in this dictionary. The most common is: the 21st letter of the Greek alphabet (Φ, φ), often used as a symbol in science and mathematics.
What is the difference between "phi" and "pi"?
Phi (Φ, φ) and pi (Π, π) are both letters of the Greek alphabet used as mathematical symbols, but they represent different constants: phi commonly denotes the golden ratio, approximately 1.618, while pi denotes the ratio of a circle's circumference to its diameter, approximately 3.14159. They are unrelated numbers that simply share Greek origin.
What is "phi" used for in science and mathematics?
Phi is used as a symbol across many fields of science and mathematics, most notably to represent the golden ratio, approximately 1.618, a number linked to certain proportions found in geometry, art, and nature. It also appears in physics and statistics to denote other specific quantities depending on context.
Where does "phi" fall in the Greek alphabet?
Phi is the 21st letter of the Greek alphabet, written as Φ in its uppercase form and φ in its lowercase form. It comes after chi and before khi in some traditional orderings, though modern Greek places it among the later letters of the alphabet.
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